blog link in header

hi everyone,
This seems pretty simple but i can’t find a good website with instructions.
I’d like to have a link called ‘Blog’ in my header that will go my blog. All other links in the header are pages. I’m trying to do something pretty much exactly like www.ads-software.com where they have pages but also a blog link in the header.

i’m not using a wordpress theme if that makes a difference?
please help!